A GIANT asteroid is set to hurtle past our planet next month.

The space rock - described as "half the size of Everest" - will be visible from Earth as it comes chillingly close to us.

Official name 1998 OR2, the asteroid is set to pass by earth just before 10am on April 29, when it will be 3.9 million miles from our planet.

This may sound far away, but it is close enough to be considered a "near Earth object" (NEO) by NASA. The space agency considers anything passing within 120 million miles of Earth a NEO.

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How to see the asteroid

If you have a telescope at home you should be able to see 1998 OR2 as it skims passed earth.

But, for those without, you can actually watch the asteroid pass us online, as the Virtual Telescope Project in Rome will host a free public viewing of the asteroid.

NASA discovers roughly 30 NEOs every week.

The space agency explained: “Experts estimate that an impact of an object the size of the one that exploded over Chelyabinsk, Russia, in 2013 – approximately 55 feet (17 metres) in size – takes place once or twice a century.

“Impacts of larger objects are expected to be far less frequent (on the scale of centuries to millennia). However, given the current incompleteness of the NEO catalogue, an unpredicted impact – such as the Chelyabinsk event – could occur at any time.”

What's the difference between an asteroid and a meteorite?

Asteroid 1998 OR2 is roughly between 1.8 and 4.1 kilometres in diameter.

At the higher end of that estimate, it suggests the space rock could be around half the size of Mount Everest, and taller than Japan's Mount Fuji.

Nothing has struck earth with apocalyptic damage for 66 million years, when an asteroid wiped out the dinosaurs.

Asteroids are larger rocks that orbit around the sun.

Often, due to gravitational pulls from planets, they can be moved off course and can collide with planets and other debris in space.

A meteor is a smaller rock that flies around our solar system.

When these crash down through earth's atmosphere, they burn up and vaporise, causing what we know as a "shooting star".